[racket] introspecting names and versions of all planet packages used by a program

Can a program running in Racket VM introspect on itself to determine the 
names and versions of PLaneT packages that the program uses?

I tried poking around with environment introspection, and trying to 
follow module use graph that way, but no luck so far.  Maybe this is 
something that modules rightfully hide?

The reason I want this is for the About box of an app: 
"http://i.imgur.com/TofUX.png".  I'd like to acknowledge the PLaneT 
packages the app uses, and indicate the version numbers for 
support/debugging purposes.  I'd like to do this programmatically.

If I can't do this introspection, then I have a bunch of alternatives in 
mind that might work, but they're all messy and/or a chunk of work.

Neil V.